Binaural flying



Dec. 28, 1937. DE F REZ 2,103,248

' BINAURAL FLYING Filed March 7, 1955 4 Sheets-Sheet 1 INVENTOR Luzs deFlarez mwm AT ORNEY Dec. 28, 1937. L. m: FLOREZ I 2,103,248

BINAURAL FLYING Filed March '7. 1935 4 Sheets-Sheet 2 INVENTOR Zzas deFlorez ORNEY Dec. 28, 1937. L, DE F REZ 2,103,248

BINAURAL FLYING Filed March '7, 1935 4 Sheets-Sheet 3 INVENTOR Luzs deFloreZ AT ORNEY Patented Dec. 28, 1937 UNITED STATES PATENT OFFICEBINAURAL FLYING Application March 7, 1935, Serial No. 10,195

14 Claims. (01. 177 311) This invention is related to the fact that thedirection from which a sound reaches the ears is sensed binaurally andthat through binaural faculty, a course can be set in respect to suchsound. Sound can thus serve as a referencefor direction or attitude.

It is known that flight can not be maintained without some referencepoint or plane. Thus a pilot in a fog, without instruments,-can not con-10 sciously maintain flight. This need for some reference applies evento bird flight as demonstrated by tests with hooded birds.

Heretofore, the needed reference for blind flying has been provided byvisual. observation :5 of certain instruments, such as turn and bankindicators, artificial horizons and the like. An objection to instrumentflying is that it requires the almost complete visual attention of thepilot and requires that the pilot immediately and cor- CJI readings intonecessary corrective measures in the handling of the craft.

Special objects of this invention are to avoid these difiiculties andobjections, to utilize sound as a reference point and to make use of thebinaural faculty in such a way as to render the act of flying as nearlynatural and instinctive as possible.

Other objects are to provide eflicient, reliable y) and practicalapparatus for conveying the directional information to the pilot in amanner that can be sensed in this binaural fashion.

Additionl objects and the novel features of the invention will appear orare set forth in the fol- 35 lowing specification.

- The drawings accompanying and forming part of the specificationillustrate a number of different embodiments of the invention, but itwill be appreciated, as the invention is understood, that .p thepractical form of apparatus used may vary within wide limits, all withinthe broad scope of the claims.

Fig. 1 is a representation largely diagrammatic of one form theinvention may take. Fig. 2 is a similar view of another embodiment.Figs. 3 and 4, like the preceding, are generally diagrammaticillustrations of other possible forms of the invention.

In the several views, binaural signal receivers are indicated at l, 8.These may be the two telephones of an ordinary headset or otherusual orspecial binaural receptive devices.

The signal, which in the end reaches the ears of the pilot as sound, maybe generated locally 55 or at some distant point.

.7 rectly translate the meaning of the instrument Both possibilities areillustrated in Fig. 1, where there is shown a wind driven generator 9,to be mounted in some favorable position on the craft and a radioreceiver l0, having a suitable antennae system H, for picking upbroadcast, beam, 5 radio telegraph or other radio signals.

A changeover switch is indicated at i 2, to enable utilization of eitherlocal or remote signal energy.

Suitably connected in the signal circuit are indicated the speakers orsound reproducers l3, it, in spaced relation and of equal output.

Opposed to the speakers are indicated individual microphones or pickupdevices l5, l6, individually in circuit at l1, l8, with the binauralsignal receivers 1, 8. v e

The speakers l3, l4 and associated microphones l5, l6, are variablyrelated, acoustically, electrically or mechanically, or in a combinationof these ways, and in such manner as to create the desired binauraleffect. In this particular illustration, the transmitters l5, l6, forthe individual ear phones I, 8, are mounted on parallel linkage l9,constructed to hold them in an intermediate position, opposite andequally distant from the sound reproducers l3, l4, and to shift eitherone toward one reproducer, while retracting the other from the otherreproducer.

These adjustments have the effector creating both phase difierences andintensity variations, a lead in phase being established by the approachof one microphone and recessionv of the other, with attendant increasein intensity at the approachlng microphone and loss of intensity at thereceding microphone. 5

head phones, providing binaural signals of marked characteristics. It isrecognized that phase difierence becomes less of a factor as the pitchof a sound increases, due to the reduction in the time betweenvibrations and that at the higher pitches the directional effect isdetermined largely by difference in intensity. The human mind isaccustomed to the phase differences for the lower pitch sounds and tothe intensity effect for the higher pitch sounds and for purposes oforientation, the mind expects and relies on phase difference for thelower pitch sounds and does not expect it or rely so much on it for therelatively high pitches. The gradationin effect of these changes inphase,with pitch, seems entirely natural andproduces no unusual effectin sensing direction.

The phase and intensity variations'are automatically effected in theillustration by means of a turn sensitive instrument, such as a turn andbank indicator 20, gyro compass or the like, acting through aservo-motor 2|, or equivalent, to operate a crank 22 and link 23, forshifting the microphone linkage.

With the changeover switch l2 in the position 4 indicated in full linesin Fig. 1, the speakers i3,

microphones l5, IS, in the intermediate full line position, equidistantfrom speakers i3, 14, the

sounds picked up at |5, It, will be of equal intensity and in phase andthe pilot through the binaural faculty, will sense the source of soundas directly in front and steer accordingly. If the ship veers to theleft, in the example, the turn i sensitive instrument, through theconnections indicated, will effect a shifting of the right hand pickupl6, toward speaker |4,.and recession of the left hand pickup l5 fromspeaker l3, as indicated in "the broken lines to effect an increase inintensity and an advance in phase of signal in the right hand receiveras compared with the signal in the left hand receiver. Consequently, thepilot, through his binaural sensibilities, is given the impression thatthe sound is toward the right and by a simple natural reaction, willswing the ship toward the right, back to the true course indicated bythe equality of signal in both ears.

With appropriate controlling connections from the turn sensitivemechanism, phase and intensity variations may be amplified or evenexaggerated, as desired. While experience has indicated that combinedphase and intensity variations are the most readily recognized, as inline with the normal hearing functions of the ears, it is possible thateither one or the other of these variations only may be utilized forcourse directing purposes. In blind flight, it'has been-found thatprobably the mostimportant control under ordinary circumstances, is theturn' of the ship. This has lead to the development of the generallyaccepted one-two-three'system in which turning movement of the ship isfirst stoppedbefore other conditions are corrected. Many ships are .soinherently stable that if turning is properly controlled, it is possibleto operate, even in rough air with turn'control alone. Therefore, thebinaural reference to turn, alone, in a ship of proper stability enablesflying to be safely accomplished.

With the switch l2 thrown to the right in Fig. 1, the local wind drivengenerator 9, can he utilized as the source of signal energy, theoperation otherwise being then as before described. Additionalindication is derived in this case however, in that changes in air speedas effected by diving or climbing, will occasion changes in frequencyand hence vary the pitch of the sound heard by the pilot to notify himaccordingly of such changes in the attitude of the airplane or othercraft. Fig. 2 illustrates a construction by which changes in phase andintensity are 'efiected electrically. In this view the wind drivengenerator 9 includes a star wheel form of rotor 24, cooper-' ating withgenerator poles 25, 25. The latter polar member 26 is shiftable aboutthe axis 21,

through the medium of link 28, lever 28, link 38 ing 34,. serving theleft head phone 1.

and levers 3|, 32, the latter being connected with link 23, operated bythe servo-motor 2|.

The polar members 25, 28, carrying windings 33, 34, are connected bywiring 35, 38, across the non-inductive potentiometer resistances 31,38. One head receiver 1 is connected by its wiring H, with one end ofresistance 21 and with movable potentiometer contact 39, and the otherhead receiver 8, is connected by its wiring 18, in the reverse order topotentiometer resistance 38, and

to the adjustable potentiometer contact 40. These two variable contactsbeing carried by levers 3|, 32, which are connected by link 30, itfollows that with movement of the crank 22 of the servo-motor,potentiometer resistance will be cut into circuit of one phone, whilebeing removed drop on the potentiometer at 31, across. the left handhead phone 1, increase the potentiometer voltage drop at 38, across theright hand head phone and introduce a lag in phase into the wind- Conse-'quently, there will be both an apparent lead in phase and an increasein intensity in the right hand ear phone, simulating the effect ofturning leftward away from a sound source. The pilot to fly toward thesound source naturally will then swing his ship back to the right tobring it again in the line of projected flight. A swing to the rightwill effect the reverse operations.

The structure illustrated in Fig. 3, involves the general features ofthat shown in Fig. 1, but with the substitution of an independentdirectional receiving set for each of the speakers l3, I4. The two radioreceivers are designated 4|, 42, having their outputs directly connectedto speakers l3, l4, and equipped with directional vertical loops 43, 44,in planes equi-angular counter-clockwise and clockwise respectively tolongitudinal axis of the ship. By means of double-throw cross connectingswitches 45, 46, each receiver may be connected with either antennae.

In use, the receivers 4| and 42 may be first tuned to a source of radiosignal in the direction of proposed flight andadjusted to the same gainby connecting first one and then the other with the same antennaandadjusting until the intensity is brought to the same in both ears.

the intensity and phase will be the same in both ears. Deflection fromthe intended line of flight however will effect, as before,displacementin phase and variations in intensity, giving the pilotimmediate indication that he is swerving off the course and guidancebinaurally by which he can bring his ship immediately back on thecourse.

Double throw changeover switches are indicated in Fig. 3, at 41, 48, bywhich the outputs of the two. receivers 4|, 42, may be sent directlyinto the binaural receivers I, 8, instead of through the medium of thephase displacement and intensity changing couplings between speakers It,i4, and the sound pickups i5, i8. noted that with switches 41, 48,turned to the dotted line positions, the microphones orpickups l5, IS,with their energy sources 49, 50, will be cut out of circuit and thebinaural receivers I, 8, cut in on the receiver outputs through thebranch leads 5|, 52. If desired, in this latter use, the speakers l3,It, may be cut out of action. Under the last described-conditions, theseparate receivers with directional loop antennae will give intensityvariations in the binaural receivers, notifying the pilot instantly ofany turning oil the course and enabling the pilot to naturally and moreor less instinctively swing the ship back into the line of desiredflight.

The Fig. 4 construction is.generally similar to that first illustrated,except that the signal output from the non-directional receiving set orwind driven generator is applied to the binaural receivers through apotentiometer controlled directly or indirectly from the turn sensitiveinstrument 20. In this illustration, the turn sensitive device isindicated as connected at 53, with the movable arm 54, of thepotentiometer, which arm has common connections 55, with both binauralreceivers, the latter having individualconnections 56, 51, with oppositeends of the potentiometer resistance 58, so that with change indirection, intensity of signal will be increased in one ear, while beingreduced in the opposite ear.

Thus in the illustration, with turn to the right, the potentiometer armwill be displaced to the right as indicated in the broken lines, toincrease the signal in the left ear and reduce signal strength in theright ear, giving the pilot the sense of turning right-handedly awayfrom the signal source and urging him to swing left, back onto thecourse.

Fig. 4 illustrates further the special feature of a quiet or silent zonefor indicating on the course position. This is shown simply as a switch59, by which a central section 60, ofthe resistance may be cut out ofcircuit, so that with the potentiometer arm in a generally centralposition, no signal will be heard in either ear phone. Upon deviationfrom the intended direction however, the signal will be cut in on theear phones as before described. This construction or equivalent, enablesthe pilot to pick up the direction signal and after setting his course,cut out the signal and keep it out, so long as proper direction ismaintained. The instance of signal reception in addition, then becomes anotice or warning of deviation from the course. Checking of the signalmay be effected at any time by simply closing switch 59.

With the possibility of signal reception from two different sources asin Figs. 1 and 4, there is always the opportunity of checking oneagainst the other. This same feature may be incorporated in the systemsillustrated in Figs. 2 and 3.

While it may be the more natural way to pick up a sound source and thenfly toward that source, it is contemplated that the reverse proceduremay be followed, that is, to use the signal as a warning notice, as in aconstruction on the order of Fig. 4, where a signal is heard only whenthe pilot turns off the course to one side or the other.

The use of a radio receiver or receivers as the It will be signal sourcehas special advantages but-subjects the pilot to conditions at thetransmitting station and the intervening distance. The wind driven orlocal signal generating hook-up makes the entire system aself-sufficient unit. A combination proportional to the extent of turnor "deviation from direction, so that the pilot will have a pro--portional or quantitative sense of the change and can apply correctivemeasures accordingly. Many changes in structure are possible, so theterms employed-herein should be considered in a descriptive rather thanin a limiting sense, except possibly as limitations may be imposed bystate of the prior art. Thus thevariable connection with the binauralreceivers may be effected in various ways, as for example by absoluteconnection and disconnection or merely modification of resistancein thetwo phone. circuits. The directional loops indicated at and 44 in Fig.3, may be of the flat type, instead of upright as shown. f

In all the various forms of the invention, the

piloting, steering or flying of the craft is made quite natural andinstinctive through the creation of a sound reference and theutilization of the binaural faculties to locate or sense the directionof that reference. The ears are thus made use of in their normal andnatural capacity of sensing direction without taking the attention ofthe pilot away from other duties. While the turn indication is the mainrequirement, particularly for safety in blind flying, the inventioncontemplates other indications, such as the angle or pitch indicationprovided by the local wind driven form of signal sourceillustrated inFigs. land 2, where with change in angle, as in diving, the frequencyand hence the pitch of the signal will increase, while inclimbing thefrequency and correspondingly the pitch will drop. In blind flying, thischange in signal tone, regardless of whether the ship is in a turn or onthe straight course, will indicate to the pilot if the ship is nosing'upor down.

What is claimed is: v I

1. Apparatus for the piloting of aircraft or the like, comprising incombination, binaural receivers, a turn indicator and means controlledby said turn indicator for impressing on said receivers signals varyingin phase and in intensity in accordance with direction of turn.

2. Apparatus for the piloting of aircraft or the like, comprising incombination, binaural receivers, a turn indicator, means controlled. bysaid turn indicator for impressing on said receivers signals varying inphase and in intensity in accordance with direction of turn, said meansincluding variable resistance and signal phase displacement mechanismactuated by said turn indicator.

3. Apparatus for the piloting of aircraft or the like, comprising incombination, binaural receivers, a turn indicator, means controlled bysaid turn indicator for impressing on'said receivers signals varying inphase and in intensity in aceluding variable resistance and signal phasedis.- placement mechanism actuated by said turn indicator, said phasedisplacement means operating at audio frequency and s'aidsignalmeansincluding a receiver of radio frequency, 7 4. Binaural pilotingapparatus, comprising in combination with aircraft, a radio receiver onsaid aircraft, binaural receivers on said aircraft, a turn indicator onsaid aircraft and means-operated by said turn indicator forvariablyimpressing the-output of said radioreceiver on said binaural receiversin accordance with direction of turn. I

5. In apparatus of the character disclosed, a turn sensitive instrument,a servo-motor controlled thereby, binaural receivers, a source of signalenergy forsaid receivers and means op-- tive instrument for selectivelyconnecting the output of said non-directional radio receiver with saidbinaural receivers in accordance with deviation from direction.

8. In apparatus as disclosed, the combination of binaural receivers, asignal source, a turn sensitive instrument and connections between saidsignal source and the respective'binaural re-- ceivers, including meansoperable by said turn sensitive instrument for introducing phasedisplacement in said binaural receivers in accordance with deviationfrom direction.

9. In combination, radio receivers having directional antennae in spacedrelation, binaural receivers connected respectively with said radioreceivers, and turn sensitive means for introducing diiferences in phasein the binaural re- 9,108,248 cordance with direction of turn.fisaidmeans in aeivers in accordance with deviation from direcon. v

10. In combination, a signal source. makers energized thereby, pickupdevices movably related to said speakers, binaural receivers .connected+-with said pickup devices and turn sensitive means for effecting theshifting of said pickup devices reverseiy toward and awayfrom saidspeakers. 11. Binaural flying apparatus, comprising in -combination withaircraft, binaural receivers on said aircraft, a radio receiver on saidaircraft coupled to said binaural receivers and means on said aircraftincluding an instrument shiftable in accordance with change ofdirection: of flight of said aircraft for introducing varying binauraleffects in the output of said radio receiver in accordance withdeviation from direction.

12. In the flying of aircraft, an instrument sensitive to change inattitude, binaural receivers,signal means for said receivers and meansoperable by said instrument for varying the phase and intensity of thesignals from said signal means in said binaural receivers in accordancewith deviation from predetermined attitude and. for simultaneouslyincreasing intensity with ad- 'vance in phase of signal in one binauralreceiver while simultaneously reducing intensity with retardation ofphase in the other binaural receiver.

13. .Apparatus for the piloting of aircraft, comprising in combinationbinaural receivers, a signal generator of variable frequency inaccordance with air speed and means for selectively impressing signalenergy from said generator on said binaural receivers in accordance withdeviations from predetermined flight attitude and including mechanismfor also shifting the phase of the signals in the binaural receivers inaccordance with deviation from predetermined flight attitude.

14. In apparatus for maintaining aircraft flight, the combination ofmechanism sensitive to devlation fromv predetermined flight attitude, a

servo-motor controlled thereby, binaural receivers, a source of signalenergy for said re- .ceivers and means operable by said servo-motor forselectively directing energy from said signal source to said binauralreceivers in accordance with deviation from said predetermined flightattitude.

' LUIS on FLOREZ.

